Shell: csu - cut sort unique with count

Below is simple script to cut the specified field ("|" separated) from flat file, sort unique and displays with count.

###### Start Script #############
#!/bin/sh

if [ $# -lt 1 ]
then
echo "Usage: $0 <filed_number> <filename>"
exit;
fi

cut -d"|" -f$1 $2|sort |uniq -c

###### End Script ###############

How to run
copy the contents from start script to end script and place in a file named csu

$ chmod a+x csu
$ copy the csu to bin
$ csu 2,3 filename
12 523|install_Mac.pdf
12 e23|install_Mac.pdf
12 r23|install_Mac.pdf
10 t23|install_Mac.pdf
2 t23|install_Win.pdf
11 y23|install_Mac.pdf
1 y23|install_Win.pdf